1. Field of the Invention
The present invention relates to a zip fastener, a method for joining two edges of material together with a zip fastener and apparatus for making a zip fastener. In particular, the present invention is concerned with zip fasteners for joining together two edges of patterned material where the pattern needs to match across the join.
2. Description of the Related Art
Zip fasteners are commonly used for joining together two edges of material. They may be used for providing a closeable slit in a unit e.g. as in a dress zip, or they may be used for joining two separate pieces of material together. They are widely used in a upholstery, clothing etc., with almost any type of material. In many situations, a zip fastener will be used to join together two edges of patterned material. A particular example is the manufacture of car seat covers. In this situation, it is important that the pattern on the two edges of material matches.
Matching two such patterns is an awkward process. A conventional zip fastener has two stringers which are formed from a plurality of coupling elements located on an edge of a tape. The edges of material to be joined are attached to the respective tape and the zip fastener is closed by engaging the coupling elements with a slider. In many situations, it is not practical to attach the material when the zip fastener is closed. Therefore, the zip fastener stringers need to be marked so that the pattern on the edges of the material can be matched with the corresponding position on the stringers.
A method of doing this has been to mark the tapes of the zip fastener stringers with a pen. However, this has many disadvantages. For example, during handling of the pen mark can be rub off. Also, the tape must be marked on its upper and lower surfaces. It is awkward to accurately align pen marks on both of these surface.